The invention relates to a metal-cutting tool and, in particular a rotary cutting tool and a method of making the same. In one aspect, the rotary cutting tool can be, for example, a reaming tool.
Reamers typically are used for the finishing of boreholes. In this context, highly accurate roundness and straightness, as well as a high surface quality of the inner wall of the bore, are of material importance. In the case of a plurality of simultaneously machined boreholes, a precise coaxiality of a plurality of boreholes is additionally of importance. A typical application is the inner surfaces of bearing components, for example in engines.
In order to obtain the best possible drilling results (roundness, straightness etc.), in reaming tools of this type, which often have only a single reaming cutter, guide elements, usually in the form of bars, are attached to the periphery of a tool main body. The radially outermost points of the guide elements lie at a same radial distance to the center axis and, upon an imaginary rotation about the center axis, define a guide circle. Correspondingly, the cutter, upon rotation about the center axis, defines a cutting circle. The diameter of the guide circle is here consistently smaller than the diameter of the cutting circle.
In the machining operation, the tool is deflected due to the generated metal-cutting forces until the guide elements come to bear against the inner wall of the bore. During such operation of the reaming tool, heat is generated at the interface between the cutting insert and the location where material is being removed from a workpiece (i.e., the insert-workpiece interface) and at the interface between the guide elements and the inner wall of the bore (i.e., the guide element-bore interface). It is well-known that excessive heat at the insert-workpiece interface and the guide element-bore interface can negatively impact upon the useful tool life of the cutting tool and its various components. As can be appreciated, a shorter useful tool life increases operating costs and decreases overall production efficiency. Hence, there are readily apparent advantages connected with decreasing the heat at the insert-workpiece interface and at the guide element-bore interface. Thus, it is known to provide a coolant material to these insert-areas to decrease the heat and increase the useful tool life.
However, it will be appreciated that most known systems for providing a coolant material to the insert-workpiece interface and/or to the guide element-bore interface are difficult and/or expensive to manufacture while still maintaining the overall integrity of the cutting tool components and while also being able to efficiently deliver and direct the coolant material to the desired areas. Thus, it would be desirable to provide an improved metal-cutting tool and, in particular a rotary cutting tool such as, for example, a reaming tool that overcomes limitations, shortcomings and/or disadvantages of known such tools.